The present invention relates generally to a response message transmitter in a portable mobile radio communication apparatus such as a portable telephone apparatus, a cordless telephone apparatus, or the like, and more particularly to a response message transmitter in a cellular mobile telephone apparatus, which is operable to notify the calling party when the cellular mobile telephone apparatus receives an incoming call but the user cannot immediately answer a calling party, for example, because the user is driving a vehicle or the like, or because the user is in a place where the use of cellular mobile telephones and so on is restricted, or the like.
With a currently used cellular mobile telephone apparatus, when an incoming call is received, although the user should respond to the call, the user is not always immediately ready to do so. Particularly, when the user is driving a vehicle or the like, the user cannot immediately respond to a call. Conventional cellular mobile telephone apparatus have a special function of answer pending a call so as to cope such a situation. This function is invoked by depressing a pending button, when the user cannot immediately accept a call, to notify a calling party through a base station that the user cannot immediately respond to the call although the telephone line connection has been established therebetween, to reduce the volume of, the telephone ring and to permit the user to initiate a communication when the user is ready to do so. Such a cellular mobile telephone apparatus is disclosed in JP-A-8-163208.
However, such a simple response message function is not sufficient to notify a calling party of specific reasons for which the user is "pending" a call. More specifically, the calling party cannot know whether the user cannot respond to a call because he or she is now in a place where the use of cellular mobile telephone apparatus is restricted, and is moving from that place; or because the user is now busy with other business; or because the user is driving a vehicle or the like so that he/she cannot respond to a call before he/she stops driving. It can therefore be thought that the pending state extends over such long time period that the calling party gives up the call, as the case may be.
With the conventional cellular mobile telephone apparatus as described above, the user suffers from an inconvenience when an incoming call is received but the user cannot immediately respond to the call because the conventional cellular mobile telephone apparatus does not have any means for notifying a calling party of the current situation of the user. In addition, the calling party cannot know the current situation which the user of the destination cellular mobile telephone apparatus is experiencing.
According to certain data, traffic accidents related to the cellular mobile telephone apparatus during the operation of a vehicle happen more while drivers are looking for their cellular mobile telephone apparatus for placing a call or for responding to an incoming call than while they are actually communicating. The conventional cellular mobile telephone apparatus have not at all been designed in consideration of improvements, particularly, in the usability addressed to such a situation.
Furthermore, it has been found from exemplary usage that when the users carry their cellular mobile telephone apparatus with them, most of the users keep it in a bag or the like. Thus, even though the user is in a situation in which he/she cannot immediately respond to an incoming call, the user must once take the cellular mobile telephone apparatus from his/her bag, each time an incoming call is received in such a situation, for invoking the "pending" operation. It can therefore be seen that the conventional cellular mobile telephone apparatus have not been designed in any consideration of improvements in the usability addressed to such a situation.